I showed everyone here the lumber carrier build I did. A modeler I know from Japan sent me photos of some bike chain he used on his Fordson tractor drive made in Japan. He sent me a link to where he purchased it on Amazon. Anyway, currency conversion would have been less than $20 USD for the kit. When I looked the part up on Amazon on the US side of things they wanted $89 + $10shipping for the same part. I decided to try and make my own. So, I downloaded a CAD file of bike chain and printed it in a flexible resin.
First print, 9 minutes later I got out the 4 pieces I printed on the build plate seen in the photo.
The resin is clear, but they make pigments to color it. I added black tint but it still looks pretty clear. The size I estimated scale on and it came out too small.
I resized it and ran a second batch (14 minutes) .
The resin is very flexible, almost like a rubber band. I might mix some flex with some standard black resin so it isn't so floppy to handle.
Here is a photo of the 2nd batch draped on the lumber carrier for size comparison.
Here is the chain with the black regular resin added to the flex. It's perfect. Flexible enough to position without breaking but stiff enough to not be a limp noodle. 
You can see in these next two photos the individual links
Here is the last one showing in by the lumber carrier
